This invention relates to garment fastening devices of the kind comprising a pronged fastener component adapted to be applied to one face of a portion of garment fabric material, and a backing member adapted to be applied to the opposite face of said portion of garment fabric material. The pronged fastener component has integral attachment prongs which penetrate through the thickness of the garment fabric material and are clenched on said backing member to clamp the latter to the material and thereby firmly secure and anchor the fastener component in place.
The invention is especially concerned with the backing member structure and an object of the invention is to provide for such garment fastening devices an improved simple form of effective backing member adapted to cover and conceal the clenched prongs of the pronged fastener component. The pronged fastener component may, for example, be a pronged hook component of a garment hook-and-eye fastener for the waistbands of trousers or skirts.
Various forms of backing member structures have hitherto been proposed which provide a covered internal space forming a clenching recess or recesses to receive the prongs of a pronged fastener component and which have integral interior cam surfaces to clench the prongs into said internal space. But the structural desgins of many of these prior proposals have often been bulky and such that the internal space forming the clenching recess or recesses has been relatively large. The control and guidance provided for the prongs has been insufficient reliably to avoid an unacceptable high proportion of defective clenchings of the prongs and to ensure a clenched configuration of maximum effectiveness, especially in mass production use.
It will be appreciated that provision for the pronged fastener component of a permanent secure reliable anchorage which will not become loose or unduly weaken the garment material under the stresses of working conditions is a major practical requirement. Factors important in relation to the above requirement include (1) the ability of the backing member, when provided with integral cam clenching surfaces, to control and influence the manner in which the prongs are clenched, even if the prongs are initially slightly misaligned or distorted, (2) the ability of the backing member to maintain and distribute an effective clamping pressure upon the garment material, and (3) the mechanical strength and rigidity of the backing member which is relevant to the possibility of accidental deformation or distortion before or after use.
Backing members of the general form mentioned, which include integral clenching cam surfaces and which cover and conceal the clenched prongs are particularly preferred when it is required to secure a pronged fastener component to a fully made-up garment so that the prongs are passed through a full thickness of garment material and the backing member is positioned on an exterior surface and may, in use, be exposed to view. Consequently, overall size and shape, bulk, and close fitting against the garment material, are further important characteristics of backing members of this general form which affect the commercial acceptability of the product.
Having regard to all the above factors the desirability has been recognized of providing improvements in the overall structural design of such backing members.